Data transmission systems such as Universal Serial Bus (USB) 2.0 may benefit from signal conditioning to strengthen deteriorated signals due to transmission losses. Generally, a signal conditioner may comprise a receiver, an equalizer, and a transmitter. Such a signal conditioner often is uni-directional and is connected in series in data lines. That is, signals can flow in only one direction through the equalizer. For half-duplex or full-duplex data transmission, two signal conditioners are required, one for each of the two transmission channels that have opposite directions of data flow. This configuration often results in high circuit complexity and low power efficiency. For USB 2.0 system, this configuration will not be functional since the system configuration protocol cannot be understood and the communication between the host and device will be interrupted.